4 ms·

Interesting logic. The author quotes Satoshi's definition of blockchain which doesn't preclude private blockchains at all. He then quotes a "more accessible" d

Interesting logic. The author quotes Satoshi's definition of blockchain which doesn't preclude private blockchains at all. He then quotes a "more accessible" definition that explicitly precludes private blockchains. So fine, if you define blockchain as being open then, sure, it can't be private. He then has a flowchart that doesn't refer to either definition and follows that with a set of reasons why people want a private blockchain and refutes them. Two of these are fine: private data and access control. Two of these are just plain strawmen: scaling and confidence. And of the 2 reasons that do make sense he makes clearly incorrect statements: > A blockchain has to be public in order to ensure permanence or immutability. No it doesn't. A restricted group of people can use identically the same features that a public blockchain has to manage eventual immutability. If that weren't true then it would imply that, say, the Bitcoin blockchain would not have it's current immutability properties if only its current users could access it. But that's simply not true. > A blockchain has to be permissionless in order to ensure permanence. Again, no it doesn't. Just because you restrict who writes to the end of the chain says nothing about the rest of the chain. Now, it would be a reasonable argument to say that the useful properties of a blockchain are only available to people who have read access to the whole blockchain. And I'd agree with that. But he's not making that argument, as far as I can see, so his actual argument is either tautological or verifiably wrong.

berkes 8y ago
> the Bitcoin blockchain would not have it's current immutability properties if only its current users could access it. But that's simply not true. Interesting point. But I think this evolves around what makes "private" and what not. Is a network of ~10.000 anonymous nodes "private" if you now close it? I guess it would be called "permissioned" and not "private". Further, my point is that when you would close the current network and disallow anyone to write and read from it, other than the currently online ~10.000 nodes, disallow new wallets and participants (making it private) you'd loose three things, essentially rendering the blockchain unusable: breaking it's immutability: * There would be no new miners. * There will be no increase in usabiltity: no future gain. These two things will logically cause centralisation of the existing mining. After all: no new miners can join, and only miners can drop out. A typical "private blockchain" so not one that started out public, grew large and then turned private, but one that starts out private, therefore has no need for PoW at all: it makes no sense, and adds no security that is not already there (through enforcements of access controls). Hence either the PoW is just nonense and (even more so) a waste of energy. Or it is left out. And a blockchain without a PoW is just a DAG tree. Or cryptographically signed logbook. Which can be useful in itself. But which is not a blockchain.

berkes 8y ago

> the Bitcoin blockchain would not have it's current immutability properties if only its current users could access it. But that's simply not true. Interesting point. But I think this evolves around what makes "private" and what not. Is a network of ~10.000 anonymous nodes "private" if you now close it? I guess it would be called "permissioned" and not "private". Further, my point is that when you would close the current network and disallow anyone to write and read from it, other than the currently online ~10.000 nodes, disallow new wallets and participants (making it private) you'd loose three things, essentially rendering the blockchain unusable: breaking it's immutability: * There would be no new miners. * There will be no increase in usabiltity: no future gain. These two things will logically cause centralisation of the existing mining. After all: no new miners can join, and only miners can drop out. A typical "private blockchain" so not one that started out public, grew large and then turned private, but one that starts out private, therefore has no need for PoW at all: it makes no sense, and adds no security that is not already there (through enforcements of access controls). Hence either the PoW is just nonense and (even more so) a waste of energy. Or it is left out. And a blockchain without a PoW is just a DAG tree. Or cryptographically signed logbook. Which can be useful in itself. But which is not a blockchain.